How does vSAN respond when a vSAN drive is pulled from a server chassis or a host if a vSAN cluster fails without warning?
A. Components on the affected device(s) are marked as absent. vSAN will attempt to rebuild the components after the VSAN.ClomRepairDelay timer, which is set to 60 minutes by default, expires.
B. Components on the affected device(s) are marked as inaccessible. vSAN will attempt to rebuild the components the next time a host enters maintenance mode.
C. Components on the affected device(s) are marked as degraded. vSAN will attempt to rebuild the components the next time a host enters maintenance mode.
D. Components on the affected device(s) are marked as healthy. vSAN will attempt to rebuild the components after the VSAN.ComponentRecovery timer, which is set to 60 minutes by default, expires.
E. Components on the affected device(s) are marked as stale. vSAN will attempt to rebuild the components after the VSAN.ComponentRecovery timer, which is set to 90 minutes by default, expires.
https://cormachogan.com/2014/12/04/vsan-part-30-difference-between-absent-degraded-components/
Correct Answer: A
To explain the different behaviour, it is important to understand that Virtual SAN has 2 types of failure states for components: ABSENT and DEGRADED.
A component is DEGRADED if Virtual SAN has detected a failure from which it believes the component will not return (e.g. one residing on a failed disk drive)
A component is ABSENT if Virtual SAN has detected a failure, but Virtual SAN believes that the component may re-appear with all data intact (e.g. components residing on disks on an ESXi host has been rebooted)
An ABSENT state reflects a transient situation that may or not resolve itself over time, and a DEGRADED state is a permanent state.
When a component is marked as ABSENT, Virtual SAN will wait for 60 minutes (by default) for the components to become available once again. If they do not become available, and the timer expires, Virtual SAN will begin rebuilding the components elsewhere in the cluster.